With the aim of assessing volcanic hazards in the region, our project is focused on modelling the magma plumbing system and characterizing the mantle beneath the Azorean volcanoes by means of petrological, geochemical and melt/fluid inclusion analyses.
Despite the large number of geophysical and petrological studies carried out over the last few decades, there is little agreement on the internal structure of Azorean volcanoes and the number, size and location of magma reservoirs beneath the islands are poorly constrained. Establishing accurate reservoir locations and detailed parameterizations of evolving magmatic processes are of great importance for determining the amount of melt produced and/or crystallized (and thus available for eruption) and defining the degassing paths of different volatile species.
Our study will target select volcanic systems in the Azorean archipelago, with the aim of tracing each step of magma ascent from mantle source to shallow reservoirs. Powerful tools used to achieve these goals are melt and fluid inclusion analyses, coupled with petrological and geochemical investigations on mantle xenoliths and primitive lavas. Fluid inclusion microthermometry will provide information on composition and pressure conditions of fluid entrapment, depths of mineral and xenolith crystallization, and therefore depths of magma ponding. Silicate-melt inclusion microthermometry will allow us to determine the composition and chemical evolution of primary magmas and the species of trapped volatiles, which in turn provide information on degassing processes.
Several techniques will be used to characterize primary magmas, including fluid and melt inclusion microthermometry, FTIR and Raman microspectroscopy, Electron Microprobe and Laser Ablation ICPMS. Data from these techniques will allow us to model the inner structure of select Azorean volcanoes that can also be applied to other disciplines including geothermal research, volcanic and environmental risk assessment and seismic monitoring.